The invention generally relates to a wireless communication network, and more particularly, relates to an improved home location register (HLR) that implements configurable call forwarding bins in a wireless communication network.
Wireless communication is one of the fastest growing segments of the telecommunication industry. With the mobility of the wireless devices, such as cellular phones and pagers, a subscriber to a wireless service can make or receive a call or receive a message without being restricted to any particular locations. Because of the convenience provided by wireless devices, they have been widely used by average consumers.
Wireless communications are provided through a wireless communication network, which can be realized, for example, as a Signaling System 7 (SS7) network. The SS7 network uses the EIA/TIA Interim Standard 41 (IS-41) protocol, which is the standard commonly used in North America. A description of the SS7 network and the IS-41 protocol can be found in Signaling System #7, by Travis Russell, and The Mobile Communications Handbook, by Jerry Gibson, which are hereby incorporated by reference.
The SS7 network is used for switching data messages pertaining to connecting telephone calls and for maintaining the signaling network. As shown in FIG. 1, the SS7 network 100 has three different types of nodes or signaling points: Service Switching Point (SSP) 112, Signal Transfer Point (STP) 116, and Service Control Point (SCP) 122.
An SSP 112 is a local exchange in the telephone network. An SSP 112 uses the information provided by the calling party (such as dialed digits) and determines how to connect the call. An STP 116 serves as a router in the SS7 network and switches SS7 messages as received from the various SSPs 112 through the network to their appropriate destinations. An STP 116 receives messages in packet form from an SSP 112. These packets are either related to call connections or database queries for an SCP 122. If the packet is a request from an SSP 112 to connect a call, the message must be forwarded to the destination where the call will be terminated. The destination is determined by the dialed digits. If the message is a database query seeking additional information regarding a person who subscribes a wireless service, i.e., a "subscriber", the destination will be a database. Access to telephone company databases is provided through an SCP 122. These databases are used to store information about subscribers' services, calling card validation, fraud protection, etc.
As shown in FIG. 1, the wireless network is shared by multiple regions 126, such as regions A and B. In each region 126, an SCP 122 is provided. Each region 126 is further divided into a number of registration areas 132, each of which is served by a Mobile Switching Center (MSC) 136. An MSC 136 provides wireless communication services to all properly registered cellular phones 142 in the registration area.
As illustrated in FIG. 1, an SCP 122 contains an authentication center (AC) 146, a home location register (HLR) 152 and a Visitor Location Register (VLR) 156. AC 146 authenticates a subscriber's cellular phone through the use of an encrypted number called the A-Key. HLR 152 is used to store information regarding cellular subscribers in the region for which it provides services. HLR 152 also stores information identifying the services allowed for each subscriber. In addition to these, HLR 152 stores the current locations of cellular phones 142 of those subscriber's who initially activated their cellular phones through a wireless service provider in the region the HLR serves. This region is also referred to as the "home area" of those subscribers. Although not shown, a backup HLR is also provided in SCP 122. VLR 156 is used when a cellular phone 142 is not recognized by a local MSC. VLR 156 stores the current locations for the visiting subscribers.
With the convenience and wide use of cellular phones, subscribers have desired more features to be included in their cellular phones such as those available on regular telephones. For example, their cellular phones should be programmable to have incoming calls automatically redirected to another number, such as a voice mail number, in different situations.
Call forwarding bins have been implemented to accommodate the needs of the subscribers. Conventionally, four separate bins have been provided for CFU (Call Forwarding--Unconditional), CFB (Call Forwarding--Busy), CFNA (Call Forwarding--No Answer), and CFD (Call Forwarding--Default). For example, if a subscriber is engaged in a call and the CFB bin is active, all incoming calls will be redirected to the forward-to number from the CFB bin. However, if the CFB bin is inactive, a switch default number is used to redirect incoming calls, so that an announcement such as "The number you have dialed is invalid, please check your number" will be played to the calling party. Thus, in using conventional HLRs, an erroneous message could be sent to a calling party, even though he has dialed a valid phone number. This is because a particular call forwarding bin is not activated for the receiving party, even though other call forwarding bins may be active for the receiving party.
Thus, there is a need for implementing call forwarding bins so that a number of bins are checked to determine which one is active. The forwarding-to number in the active bin that has the highest priority may be used for call forwarding. Furthermore, it is desirable for a cellular carrier to configure various bins so that either the cellular carrier or subscriber can modify information, such as the forward-to numbers, in selected bins.